Heart pacer



FIG. 1 is a view in side elevation of a heart pacer illustrating our design;

FIG. 2 is a view in end elevation as seen from the direction of the arrow II of the heart pacer shown in FIG. 1;

FIG. 3 is a view in end elevation as seen from the direction of arrow III of the heart pacer shown in FIG. 1;

FIG. 4 is a plan view as seen from the direction of arrow IV of the heart pacer shown in FIG. 1; and

FIG. 5 is a plan view as seen from the direction of arrow V of the heart pacer shown in FIG. 1. 

The ornamental design for a heart pacer, substantially as shown and described. 